Chilled bees outside hive

[JWChesnut]

I have a strong hive exhibiting an odd symptom.   In the morning (nights in upper 30-mid 40's) substantial number of foraging bees are chilled and seemingly lifeless on the ground outside the hive.  The sun warms these stragglers and they slowly come back to life and return to the hive.  At least some are clearly active foragers (half filled pollen baskets), they are not exhibiting dwarf wing symptoms, and on warming can fly and orient themselves to the hive.

The hive has a upper entrance (1 inch hole in a medium) that the bees use in preference to the bottom board.  Is it possible that the entrance gets blocked by the cluster and late returning bees don't adjust to using the bottom board.

Are these just "occupy" bees protesting the dominance of the queenly hierarchy by camping out?

Have others had problems with entrance selection, should I block the entrance and force use of the bottom board?

[Finski]

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I have met the same in Spring when basic weather is cold. There  are weathers where bees can fly only with the aid of sunshine.

When bees return to home they are tired and just and just they are able to fly. They drop down into shadow and cannot rise up any more. That happens especially  before  evening.
They have a good food source nearby and it makes them fly in cold weather.

Last spring was bad I lost plenty of bees in early spring when weathers were near risk level.
Those  hives, which got sun the whole day, did not suffer much during that early period.

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Many beekeepers are happy that  their  bees fly  in low temperatures. But it is risky business and hive loose plenty of foragers in that  way.

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